Orofacial clefts, including clefts of the palate, are among the most common human congenital abnormalities. Cleft palates are characterized by a partial or total lack of fusion of palatal shelves that may involve primarily the soft palate (velum) or the entire (hard and soft) palate. In the United States, an estimated twenty infants are born with an orofacial cleft on an average day.
The patient with an unrepaired cleft palate will have impaired speech. The muscles of the palate elevate the normal soft palate (velum) to seal against the posterior pharyngeal wall to block airflow and sound from the nasal cavity during English speech for all sounds except “m”, “n” and “ng”. A cleft renders the palatal valve (the velopharyngeal valve) incompetent, which gives the patient's speech a characteristic nasal quality which is difficult to impossible to understand. Unfortunately, surgically repairing the cleft provides a valve that can completely and normally close for speech in only some 20% to 90% of patients. When valving function is poor, a condition termed velopharyngeal insufficiency, one of several second operations may be performed to improve the function of the velopharyngeal valve. However, a very significant number of patients with repaired clefts, up to 45%, speak clearly enough to communicate, even though valve closure is not complete. Because of the risk, pain and cost of the secondary operations, these patients usually remain untreated even though their speech sounds abnormal enough to be socially curious. It is primarily for these patients that the invention herein described is designed, although it may also prove to be an effective treatment for patients now undergoing larger operations for velopharyngeal insufficiency.
When the repaired cleft palate has some mobility but is not long enough to seal completely against the posterior pharyngeal wall, one method of treatment has been to augment the posterior pharyngeal wall forward toward the soft palate so that the palate can reach and seal. To accomplish this, various materials have been placed in the tissues of the posterior pharyngeal wall to bulge it forward. The simplest method has been to place a fluid material such as silicone or a paste of Teflon® particles by injection. However, because of the potential for migration of the materials away from the site of injection (with loss of the mound) to lymph nodes, tissue planes or even lungs or brain, these methods have not gained approval for clinical use.
Various treatments for cleft palate repair have been proposed. See, for example, U.S. Pat. Nos. 6,695,781; 6,592,366; 6,328,745; 6,284,284; and 6,280,191. However, better treatments are still needed.
A tissue-inert material that could be injected that would remain at the injection site would be helpful to the many patients with repaired cleft palates whose velopharyngeal valves do not close properly for speech.